Corona's displacement when set to world size, is no better than max displacement modifier and when set to screen it's useless in baked form. So what's the fuss about?

In screen mode it's not useless to me if you are working to a predetermined camera/resolution. Consider for instance a heavy-poly object which is only partially visible.You could go manually splitting the object at the edges of the camera but I'd rather use this method. It's only a tip after all, so nothing gets changed.

Also, considering possible benefits in world mode, doesn't Corona's displacement calculate adaptivity based on the detail in the displacement map as well?I honestly don't know if it works in this way or not (have to go back and look at some of the threads from when adaptive displacement was introduced) but theoretically this would make it more efficient than Max's modifier.

I too was under the impression that Corona calculated adaptivly, but I don't know any of the theory behind it. I do know however, that I never had Max's displacement or disp. mod working as good as Cornas.

In screen mode it's not useless to me if you are working to a predetermined camera/resolution. Consider for instance a heavy-poly object which is only partially visible.You could go manually splitting the object at the edges of the camera but I'd rather use this method. It's only a tip after all, so nothing gets changed.

I too was under the impression that Corona calculated adaptivly, but I don't know any of the theory behind it. I do know however, that I never had Max's displacement or disp. mod working as good as Cornas.

Nope, just tested that this morning and Corona's displacement in world mode gives very similar results as if mesh would be manually subdivided with displacement modifier on top. But with baked version you'd loose all the benefits of max's modifier stack.

In this model, adaptive Corona displacement doesn't make sense.Displacement adaptivity is on by default and it's useful when you have big, flat surface with some detailed surface.For example, a brick wall.When you have a complete curve surface, all the mesh will be subdivided in the same level.

OK. I work a lot with large low poly geometry coming from CAD or BIM programs, so I might not have subdivided it enough for the Max Disp. Mod to work well enough (much easier just using Coronas Disp. mod).

Regarding the lack of benefits when "baking" displacement, then you can't export displaced mesh without "baking" it - and that is one of my main reasons to do it.